Heretofore the use of binders and cements of the type that require specific alkaline or acidic conditions for initiation of the setting reaction has involved mixing of an alkaline or acidic component directly into the binder or cement prior to placement of the material. As the reaction times of these binders and cements are very short, often less than one hour, setting may occur before placement of the material is completed, resulting in serious flaws in the product and/or damaged or clogged mixing equipment.
Casting of hollow articles with binders or cements of this type normally involves rotating the mold to hold the paste against the interior surface of the mold until the paste has hardened. This, however, involves additional equipment and expense.
It is a primary object of the invention to control the hardening or setting reaction of binders or cements of the type which require specific alkaline or acidic conditions to initiate the reaction so that the material may be handled and placed prior to the beginning of the setting reaction.
It is also an object of the present invention to control the hardening or setting reaction of such binders and cements which facilitates the casting of hollow items without the need for rotation of the mold.